Unit 2: Nervous System: ANS Flashcards
Describe the different divisions of the peripheral nervous system (aka afferent & efferent)
Afferent [sensory] neurons - conveying info from sensory receptors towards CNS
Efferent [motor] neurons - conveying info from CNS to effectors (muscles or glands)
The neurons found exclusively within CNS are known as :
integration neurons, association neurons, or interneurons
Where does integration occur
(in terms of gross anatomy and in terms of cellular neuroanatomy)?
CNS
Synapses
Describe the different ways neurons can be interconnected to produce simple neural circuits.
A. Linear- [signal transmitted is a chain reaction; ex) knee jerk reflex] ; simple.
B. -Divergent- 1 single sensory neuron results in activity in several somatic motor neurons; ex) stepping on a tack- crossed extensor reflex
-Convergent- multiple neurons converge onto fewer neuron; ex) rods/cones in the retina
C. Inhibitory- neuron becomes excited and AP arrives at synapse > NTs released produce inhibitory postsynaptic potential
[inhibitory neuron becomes excited and generates AP but neurons it synapses with produce IPSPs and are inhibited.
D. Parallel (W/ lateral inhibition)- a neuron’s response to a stimulus is inhibited by the excitation of a neighboring neuron
E. Reverberating- chain of neurons where signals travel in a loop>feedback loop; can sustain an impulse or rhythmic pattern of firing
Define adrenergic (AKA catecholaminergic)
relating to nerve cells in which epinephrine (adrenaline) or norepinephrine (noradrenaline) acts as NT
cholinergic
relating to nerve cells in which acetylcholine acts as NT.
Muscarinic
type of NT receptor activated by acetylcholine (ACh).
associated with the parasympathetic nervous system
key role in regulating functions such as heart rate, smooth muscle contractions, and glandular secretions
nicotinic
type of NT receptor activated by acetylcholine (ACh) or nicotine.
~They are ion channels that, when activated, allow the flow of ions across cell membranes, leading to electrical signaling and physiological responses.
What are the 2 types of efferent (motor) neurons?
Somatic- specific to skeletal muscle
autonomic- associated with cardiac muscle, smooth muscle, and glands
pre and post-synaptic neurons are characteristic of what pathway?
autonomic motor pathways (not associated with somatic or sensory pathways)
Somatic NS is made up of ____________ ____________ that extend without synapsing from dendrites and cell bodies (in the CNS) all the way out to terminal endings that are synapsing onto skeletal muscles
multipolar neurons
The autonomic NS is made up of ___________ _________ synapsing onto a post-ganglionic neuron
preganglionic neuron
____________ are integration sites
synapses
Autonomic NS- does NOT produce ________ control
voluntary
preganglionic neurons are always:
Myelinated
Pre-ganglionic neurons always have cell bodies and dendrites within the CNS and always terminate onto :
dendrites and cell bodies of 2nd neuron (W/ one exception)
The primary ligand activates a receptor.
An ____1_____ also activates the receptor.
An _____2_____ blocks receptor activity.
1- agonist [mimic]
2- antagonist [blocker]
Antagonist molecules _______ receptors
inhibit
[basically like competitive binding]
in the parasympathetic NS, preganglionic neuron may originate from
the brainstem
or sacral part of the spinal card
[craniosarcal division]
in the parasympathetic NS, pre-ganglion neurons are long and -
myelinated
Sympathetic NS neurons arise from ______________________ parts of the spinal cord
thoracic and lumbar
Sympathetic regulation causes heart to-
Speed up
[antagonistic influence on effector organs]
Sympathetic stimulation has the ____________________ response
fight or flight
3 circuits of sympathetic NS stimulation
1) short pre-ganglionic neurons that synapse in the paravertebral ganglion chain [may branch]
2) pre-ganglionic neuron extends out and synapses in the adrenal medulla
3) pre-ganglionic neuron synapses in a collateral ganglion
The autonomic nervous system includes _____ neurons from the CNS to the effector.
two
How neurons are interconnected in neural circuits can result in :
emergent properties not exhibited by individual neurons
In the autonomic nervous system the neurotransmitter norepinephrine is secreted by _______.
postganglionic sympathetic neurons
The strength of a stimulus determines the ____ of an action potential.
frequency
Inhibitory neurons secrete:
neurotransmitters that trigger IPSPs
In the peripheral nervous system, ________ 1 ________ carry sensory and visceral info >CNS
and ________ 2 ________ leave the CNS and innervate organs [usually muscles or glands]
1- afferent neurons
2- efferent neurons
The sympathetic division of the autonomic nervous system is also called the:
thoracolumbar division
Describe the structural and functional characteristics of the somatic division of the nervous system.
Structural Characteristics:
Somatic/ motor Neurons
Single Neuron Pathway
Voluntary Control
Functional Characteristics:
Motor Control
Sensory Feedback
One-Way Communication: signals flowing from the CNS to the skeletal muscles
Conscious Awareness
Fast Responses
afferent neurons are typically ______________ neurons
pseudo-unipolar
Afferent neurons transmit information from: __ to ___
the periphery to the CNS
Where are nicotinic acetylcholine receptors found?
between the motor neurons of the somatic motor division and skeletal muscles
between the pre and post synaptic neurons of the sympathetic division
between the pre and post synaptic neurons of the parasympathetic division
